Make yourself irreplaceable

Finnish newspaper Kauppalehti writes that there are few ways to keep your job: 1) Learn things that other people don't want or don't know how to do. 2) Keep good relations to your boss and co-workers. 3) Ask if you're uncertain about new things.

These are good tips, but they're really not for me. Since I try to slack off and rather do something else (redtube for example) I've thought of few things that make me irreplaceable without actually doing a lot of work. Here they are:

Use old/strange techniques - If you're a coder, use Cobol or Assembler. No one will want to watch your code.

Jargon - If you write a lot, use difficult words, old latin, french, etc. and don't write text that is easily readable.

Documentation - Don't document any of the things you do and don't make any instructions.

Teaching - Don't do it. If you have no choice but to present your ideas/projects/etc. to your boss or co-workers, use Powerpoint. Make a presentation that has lot of pie charts, nice pictures and maybe even animations. Bosses love animations.

SPECIAL tip for developers: Use kludges everywhere. Even when you're coding the simplest thing with Javascript, make a moronic kludge that others will not understand.

Most of these work in the IT department, but not really if you're a cashier or a janitor. Do you have any good ideas to share about making yourself irreplaceable? Share them in comments.